It was the M120 beep commands I had in there to warn me to remove any ooze before the print starts. On the Rambo board, M120 is a beep, not so on this one, it is something else entirely. When I redid the beeps with M300's, all works.
First test print running now. Damn that thing is quiet. Well, the motion anyway. The fans not so much. I just need to find quieter 30mm fans. The printer is 3 feet behind my head, and I need to keep looking over to make sure the thing is still moving.
-David